As voters in Washington state prepare to vote on whether to require labeling of food containing genetically modified organisms, the state’s attorney general sued an industry group for violating campaign finance laws.

Attorney General Bob Ferguson said at a press conference on Wednesday that the Grocery Manufacturers Association, which opposes Initiative 522, which would enforce labeling, has spent $7 million on its defeat. Ferguson said that the grocery association didn’t establish a political action committee, but rather set up a separate account to fight the initiative.

Under state law, groups must file as a political action committee and “disclose who your donors are and how much they’re donating, so the public knows who your donors are,” he said. “That’s part of our transparent process with our elections and our campaign finance laws.”

Ferguson said the suit differs from one dismissed by a Thurston County judge earlier this month.

The group “Moms for Labeling” filed a lawsuit on a similar issue against the grocery association.